Truman Everts' "Thirty-Seven Days of Peril," Scribner's Monthly

Everts nearly perished when he became lost in Yellowstone in 1870. By the time he was rescued he weighed 50 pounds and he had severe burns from being scalded by thermal vents. But his tale of geysers and mud pots helped attract a more scientific survey of the region - and its preservation as a national park in 1872.